Specifications

176
NLUO PMC CONTRACTOR
SIGNATURE AND SEAL SIGNATURE AND SEAL SIGNATURE AND SEAL
3. Locations for Earth Electrodes :
Electrodes shall be buried at least 2 M (6’-6”) away from the building pole or object to be earthed. However, earthing
electrodes for L.C. installations should be as clode to the down conductors as possible.
Electrodes when installed in parallel, shall not be placed less than 2 M (6”-6”) apart and preferably placed at distances greater
then twice their lengths.
4. Earth Bus bar :
(a) Galvanized M.S. Flat :
The Bus bar shall be of suitable size and length, as specified in the Schedule of items, heavily galvanized and having adequate
number of drilled and tapped holes 30 mm apart, completed with G.I. bolts, nuts, washers for securely connecting the earth
leads and earth continuity conductors. The bus bar shall be fixed on wall, having clearance of 6 mm from wall with spacing
insulators with at least the numbers 13 mm (1/2’) G.I. rag bolts spaced about 0.46 M (1’6”) apart.
(b) Copper Flats :
To be used, as specified, in the Schedule of Items, where earthing requirement are more stringent. Brass bolts, nuts washers
shall be used for connections.
5. Value of Earth Resistance :
In case of installations where the load does not exceed 5 K.W. the resistance to earth shall on no account exceed 5 Ohm for
other cases the resistance shall not exceed 1 ohm.
For sub-station, the value is 1 ohm.
For L.C. installations the value is 1 ohm.